Our invention relates to an improved amplifier circuit, and particularly to an improved amplifier circuit capable of being connected in cascade to provide high gain, operating from a relatively low voltage source and still providing relatively constant gain despite changes in the voltage, and providing symmetrical operation despite changes in the voltage or temperature.
In battery powered radio or electronic equipment, the trend is toward smaller circuits with improved or increased functions, and at the same time with less power demands on the battery.
Accordingly, a general object of our invention is to provide a new and improved battery powered amplifier circuit that requires relatively little current, and that can be connected in cascade with additional circuits to provide the desired overall gain.
Another object of our invention is to provide a new and improved amplifier circuit that provides symmetrical limiting, and that has amplitude and symmetry characteristics that are substantially independent of battery voltage and ambient temperature.
Another object of our invention is to provide a new and improved amplifier that is capable of being readily made in integrated circuit form with a plurality of stages connected in series or cascades to provide the desired overall gain.
Another object of our invention is to provide a new and improved amplifier circuit that provides a gain of 18 Db, but that requires a current of only 75 microamperes at a voltage of 1.1 volts, thus making it ideal for battery powered equipment.
Another object of our invention is to provide a series or cascade of new and improved amplifier circuits, each of which provides a gain of 18 Db while requiring a current of only 75 microamperes at a voltage of 1.1 volts, thus making it ideal for battery powered equipment.
In order that the life of a battery for an amplifier be as long as possible, the amplifier should be able to operate over as wide a range of voltages as possible.
Accordingly, another object of our invention is to provide a new and improved amplifier circuit that has relatively stable gain and symmetrical characteristics despite a relatively wide variation in supply voltage, thereby increasing the useful life of a battery that supplies the amplifier voltage.
Another object of our invention is to provide a new and improved amplifier circuit that provides relatively constant gain with battery supply voltages as low as 1.1 volts.